1. Field of the Invention
The present invention relates to an image pickup system and an endoscope system, and particularly relates to an image pickup system and an endoscope system which are capable of discriminating between a predetermined region and a region other than the predetermined region in an object.
2. Description of the Related Art
Endoscope apparatuses, which acquire the images of an object in a test subject and can generate images corresponding to the images of the object, have been conventionally used widely in the medical field and the like. In particular, the endoscope apparatuses in the medical field are mainly used by surgeons for the purpose of performing treatment such as inspection and observation of the insides of living bodies.
As modes of observation using the endoscope apparatuses in the medical field which are generally known, there are for example, auto fluorescence observation in which the object inside a living body is irradiated with an excitation light and a reference light having specific wavelength bands, and a fluorescence image as an image of auto fluorescence emitted from the object in response to the excitation light, and a reference light image as the image of a reflection light which is the reference light reflected in the object are acquired, in addition to white color light observation in which the object in a living body is irradiated with a white color light, and a white color light image as the image of the object substantially similar to observation by naked eyes is acquired. As an apparatus capable of performing such auto fluorescence observation, for example, the endoscopic image acquiring apparatus described in Japanese Patent Application Laid-Open Publication No. 2001-224549 is cited.
Meanwhile, in the purpose of making it easy to find a lesion with less visibility in the white color light image, an endoscope apparatus has been proposed in recent years which can output a superimposed image with the biological information obtained from a fluorescence image and a reference light image superimposed on a white color light image.
Further, in the observation using such a superimposed image, a method is proposed which calculates the ratio of the gradation value of the reference light image to the gradation value of the fluorescence image, acquires the information of the region where a lesion is present by applying threshold processing to the calculation result, and thereafter, superimposes the information on a white color light image.